It is known that the smart card is a kind of chip card. The data is stored and calculated in the chip embedded in a plastic substrate and can be read by a card reader. In the prior art, the smart card is applied widely in many fields, such as communication, insurance, medical service, computer control system, access control system, online transaction, and identity authentication, etc. The convenience and security of the transaction are improved by the smart card on the basis of two outstanding features. One is that the identity card can define the identity of the user; and the other is that the smart card can store the encrypted data. Some smart cards can encrypt or decrypt the data by its micro-processor. In addition, the smart card has some advantages, such as mass-storage, stability, portability, and compatibility, etc.
Generally, according to the ways of use, the smart card can be classified as the contact smart card and the contactless smart card (or the non-contact smart card) with a memory and a micro-processor. The contactless smart card has an antenna and a micro-electronic chip embedded in the card body. The transaction can be processed by putting the contactless smart card close up to the antenna of the card reader without contacting the coupling sensor. The data stored in the contactless smart card can be read instantly and processed without contacting the external card reader, which saves 70% to 90% processing time in comparison with the contact card. On the basis of the advantages above, the contactless smart card is applied widely in many fields, such as medical service, traffic, social insurance, and tax, etc. So the contactless smart card becomes more and more popular and accounts for more market shares for the features of convenience and usability.
The contactless smart card technology is widely used in many payment systems for consumption, such as credit card system, debit card system, and public traffic charge system. The Chinese Patent Application No. 01145481.4 discloses a fingerprint identification technology applied in the security access control. But this patent does not include the smart card technology applied in the transaction system. In some sense, the application field of the technology is limited. The Chinese Patent Application No. 200310103495.2 discloses fingerprint identification method based on fingerprint minutiae feature matching and direction field matching. In the patent, the technology of obtaining the matching result by putting the finger of the user in the right direction field and comparing it with the stored fingerprint minutiae feature is regarded as a prior art, which is used widely in the fingerprint identification field. The Chinese Patent Application No. 01124082.2 discloses a wristwatch smart card with the function of the finger identification. The patent integrates the finger identification technology with the wristwatch IC card, which provides more functions but cannot be specified for the specific user.
The fingerprint identification technology in the patent above provides a solution for identity authentication in the security or consumption of different levels for using the smart card. In some sense, it is too complex in the process of using the smart card, which speeds up the damage of the smart card and reduces the life of the chip inside the smart card. And even a small amount of the transaction or some security of low levels needs the fingerprint identification. If the legitimate user cannot come to confirm the operation personally, he cannot consign the others to perform the operation, which is inconvenient in the event of emergency.